Biomedical subjects

B Muñoz

Publications and source records attributed to B Muñoz.

At least 55 records · Page 3Linked to original sources

PubMed1996

[Cholesterol content in longissimus muscle beef from slaughter cattle in Venezuela].

An observational study was conducted with 149 cattle, raised under tropical conditions of Venezuela (mostly grassfed), to study the relationships of sex class (62 bulls, 67 steers, 20 heifers), age by dentition (2.5; 3.0; 3.5 and 4.0 yr), physiological maturity (A or B), cattle type (17 Dairy or 132 Zebu type crossbreds), Venezuelan carcass grade (Optima, Excelente, Selecta or Superior), marbling level (four levels from "None" to "Small quantity"), carcass fat cover (four level: "Even", "Uneven", "patch-like" and "Devoid") and subcutaneous fat thickness (SFT) over the ribeye (1 = 0.1-0.2 cm; 2 = 0.3-0.4 cm; 3 = 0.5-0.9 cm and 4 = > 1.0 cm) on cholesterol content (mg/ 100 g wet weight) of longissimus muscle. Cholesterol content, as determined colormetrically, did not vary in response to the differences in sex class, age, maturity level, carcass grade, marbling level or SFT represented in the present survey. However, cattle type affected (P = 0.08) cholesterol content. Least square means analysis showed that dairy type contained 12.2 mg more of cholesterol/100 g of muscle than Zebu type. The overall mean (+/- SD) muscle cholesterol for the kind of cattle sampled herein (66.6 +/- 16 mg/100 g) was not considered to be different from those of cattle fed in other latitudes.

Animals↗

PubMed1995

Results of ophthalmic examinations of 29 alpacas.

Analysis of the results of ophthalmic examinations of 29 alpacas (Lama pacos) revealed a direct relationship among coat color, iris color, and ocular fundus pigmentation. Alpacas with light-pigmented coats had iris color that included combinations of gray, blue, and brown, and had reduced pigmentation of the ocular fundi. Alpacas with dark coats had brown irides and pigmented ocular fundi. Eleven alpacas had evidence of ophthalmic conditions, including bilateral conjunctivitis (1); formation of a superficial corneal scar (1); formation of posterior synechiae and anterior cataracts (4); development of a deep corneal scar with anterior synechiae, buphthalmia, a subluxated lens, and cataracts (1); development of focal incipient primary cataracts (2); formation of vitreous opacities (1); and development of a unilateral optic nerve coloboma (1).

Animals↗

PubMed1995

Impact of face-washing on trachoma in Kongwa, Tanzania.

Observational studies have suggested that the prevalence of trachoma is lower in children with clean faces than in those with ocular or nasal discharge or flies on the face. We carried out a community-based randomised trial in three pairs of villages to assess the impact on trachoma of a face-washing intervention programme following a mass topical antibiotic treatment campaign. Six villages in Kongwa, Tanzania, were randomly assigned mass treatment plus the face-washing programme or treatment only. 1417 children aged 1-7 years in these villages were randomly selected and followed up for trachoma status and observations of facial cleanliness at baseline and 2, 6, and 12 months. At 12 months, children in the intervention villages were 60% more likely to have had clean faces at two or more follow-up visits than children in the control villages. The odds of having severe trachoma in the intervention villages were 0.62 (95% Cl 0.40-0.97) compared with control villages. A clean face at two or more follow-up visits was protective for any trachoma (odds ratio 0.58 [0.47-0.72]) and severe trachoma (0.35 [0.21-0.59]). This community-based participatory approach to face-washing intervention had variable penetration rates in the villages and was labour intensive. However, we found that, combined with topical treatment, community-based strategies for improving hygiene in children in trachoma-endemic villages can reduce the prevalence of trachoma.

Administration, Topical↗

PubMed1995

Cigarette smoking and risk for progression of nuclear opacities.

OBJECTIVE: To examine the relationships between smoking and the 5-year incidence of new nuclear opacities and between smoking and the progression of nuclear opacities in a prospective study of a cohort of Chesapeake Bay watermen. METHODS: A total of 442 men (age, > or = 30 years in 1985) with paired, gradable lens photographs in at least one eye in both 1985 and 1990 were studied. Photographs were graded by two readers who used the grading scheme of the Wilmer Institute, Baltimore, Md, with severity ranging in decimal units between 0.0 and 4.0. Data on the smoking history of the subjects were collected by personal interviews that were conducted in 1985 and updated in 1990. RESULTS: The incidence and progression of opacities increased with age. A nonsignificant association was observed between smoking (for both current and ex-smokers) and the incidence of a nuclear opacity. The risk of progression of nuclear opacities of less than grade 3 at baseline to grade 3 or worse was 2.4-fold higher among current smokers in 1985, compared with that among ex-smokers and nonsmokers (95% confidence limits: 1.0, 6.0) after adjustment for age, baseline opacity status, and alcohol use. An 18% increased risk of progression was significantly associated with each pack-year that a subject smoked between 1985 and 1990. CONCLUSION: These data confirm previous findings that smoking is associated with a nuclear opacity, particularly with progression to severe opacities.

Adult↗

PubMed1995

Investigation of the inhibition of leukotriene A4 hydrolase.

In an effort to better understand the favorable binding interactions between the reversible picomolar inhibitor 3-(4-benzyloxyphenyl)-2-(R)-amino-1- propanethiol (1) and leukotriene A4 (LTA4) hydrolase (EC 3.3.2.6), we prepared a number of derivatives of 1-L and other related structures, and assayed their inhibition of LTA4 hydrolase-catalyzed hydrolysis of L-alanine-p-nitroanilide. The inhibition data was analyzed using a weighted non-linear least-squares curve fitting computer program developed for this purpose to fit data derived under the non-Michaelis-Menten condition of [I]t < [E]t. The free thiol is necessary for sub-micromolar binding and the enzyme prefers the R enantiomer over the S enantiomer, in contrast to the stereoselectivity displayed towards bestatin, an inhibitor of somewhat similar structure. Substitution of acid moieties around the periphery of the benzyloxyphenyl portion of 1-L leads to substantially decreased binding, suggesting that this group resides within a large hydrophobic pocket when bound to the enzyme. Possible LTA4 binding modes in the active site of LTA4 hydrolase, including a possible direct role for the carboxylic acid of LTA4 in the enzyme-catalyzed hydrolysis of leukotriene A4, are discussed.

Computer Graphics↗

PubMed1995

Isolation of a bovine uterotropic placental factor and development of an enzyme immunoassay in peripheral serum.

Bovine uterotropic placental factor (bUTPF) was obtained from bovine term placentae that had been homogenized and extracted in acidic medium. The extracts were chromatographed on Sephadex G-75, a fraction named native bUTPF was obtained, and an antiserum was generated. The native bUTPF was chromatographed on Sephacryl S-300 HR, and a 230-kDa fraction was obtained. A competitive enzyme immunoassay (EIA) was developed to determine bUTPF levels during gestation. This EIA was linear between 0 and 80 micrograms/ml (with a detection limit of 0.2 microgram/ml) and showed intraassay and interassay coefficients of variation of 11.2% and 15.5%, respectively. Bovine UTPF serum levels during gestation were determined by means of a cross-sectional study between the first month of gestation and delivery. Maximal serum levels of bUTPF were found during the first month of gestation: 7.1 +/- 1.9 micrograms/ml (p < 0.05). In another cross-sectional study, blood samples were collected from 105 cows between 8 and 25 days postinsemination (day of insemination = Day 0). Levels of bUTPF were found to be significantly higher (p < 0.05) by Day 17 compared to Day 0 (5.8 +/- 2.2 micrograms/ml vs. 1.2 +/- 0.7 micrograms/ml). We conclude that bUTPF is detected by EIA in maternal peripheral serum early during gestation in the bovine species.

Animals↗

PubMed1995

Ocular and dermatologic health effects of ultraviolet radiation exposure from the ozone hole in southern Chile.

OBJECTIVES: This study sought to investigate numerous reports emanating from Punta Arenas, Chile (population 110,000, latitude 53 degrees S), that associated acute ocular and dermatologic disease in humans and animals with excess ultraviolet-B (UV-B) exposure in the setting of the thinning of the ozone column. METHODS: Ophthalmologic and dermatologic records in Punta Arenas were systematically reviewed to enumerate sentinel diagnoses potentially associated with UV-B exposure, ocular examinations on representative animal populations were performed, and the ambient UV-B exposure in the region during the time of maximal thinning was estimated. RESULTS: No increase in patient visits or conditions attributable to UV-B exposure was seen for periods of known ozone depletion compared with control periods. Although ambient UV-B exposure was 1.6 to 2.3 times the habitual exposure on individual days, this excess exposure conferred only a 1% increase in annual exposure on the region. CONCLUSION: This study does not support existing lay reports of ocular and dermatologic disease in humans and animals that had been associated with the ozone hole over southern Chile.

Animals↗

PubMed1994

Are antioxidants or supplements protective for age-related macular degeneration?

OBJECTIVES: The relationships between fasting plasma levels of retinol, ascorbic acid, alpha-tochopherol, and beta-carotene and age-related macular degeneration (AMD) were studied in a population enrolled in the Baltimore Longitudinal Study of Aging (BLSA), in which most of the data were collected 2 or more years before assessment of macular status. DESIGN: A total of 976 participants in the study were scheduled for a biennial examination from January 1988 through January 1, 1990, which included taking lens and macular photographs. A total of 827 (85%) of the participants had fundus photographs taken, and most plasma data were available for 82% of those subjects with fundus photographs. Age-related macular degeneration was defined as neovascular changes, geographic and nongeographic atrophy, large or confluent drusen, or hyperpigmentation. A total of 226 cases of AMD were available for analysis. RESULTS: Logistic regression analyses suggested that alpha-tocopherol was associated with a protective effect for AMD, adjusted for age, sex, and nuclear opacity. An antioxidant index, including ascorbic acid, alpha-tocopherol, and beta-carotene, was also protective for AMD. Our conclusions must be tempered with the knowledge that the population under study was basically well nourished, and few individuals had any clinically deficient status. The study cannot exclude the possibility that quite low levels of micronutrients, lower than those observed in this study, might be risk factors for AMD. CONCLUSIONS: The data suggest a protective effect for AMD of high plasma values of alpha-tocopherol. An antioxidant index, composed of plasma ascorbic acid, alpha-tocopherol, and beta-carotene, was also protective. The use of vitamin supplements to prevent AMD is not supported by these data, which showed no protective effect of vitamin use.

Adult↗

PubMed1994

Prevalence of hypertension in rural west Africa.

The prevalence of hypertension in rural African communities has been reported previously to be relatively low, with prevalence rates ranging between 2.5% and 10.9%. The authors obtained blood pressure recordings in 3,588 adult residents (age > 20 years) of the Liberian Agricultural Company rubber plantation, located in rural Liberia, West Africa. Blood pressures were obtained using automated digital blood pressure machines in a house-to-house survey. Individuals with a systolic blood pressure greater than 139 mm Hg or a diastolic blood pressure greater than 89 mm Hg were referred to a central site, where three subsequent blood pressure determinations were made, the mean of which was used to determine whether people were hypertensive. The overall prevalence of hypertension (blood pressure > 139/89 mm Hg) was 12.5%. Hypertension was most common in the older women (prevalence 5.7% in women age 20-24 years old, 50% in women older than 55). Using more stringent criteria for hypertension, systolic blood pressure greater than 159 mm Hg or diastolic blood pressure greater than 94 mm Hg, 20% of women between 50-54 had hypertension and 26% of the women older than 55 had hypertension. In some ethnic groups, the prevalence of hypertension was as high as 25%. Based on these results, the prevalence of hypertension in some rural African communities may be higher than reported previously, particularly in older women and among certain ethnic groups, possibly suggesting a strong hereditary component.

Adult↗

PubMed1994

Cortical lenticular opacification: distribution and location in a longitudinal study.

PURPOSE: To examine the distribution of cortical opacification of the lens by lens quadrant in a longitudinal study. METHODS: In 1990, a follow-up assessment of a cohort of Chesapeake Bay watermen, initially studied in 1985, was performed. Four hundred thirty-seven subjects (834 eyes) had gradable cortical photographs for at least one eye in both 1985 and 1990. Cortical photographs were graded by both estimating total area and determining the quadrant with the greatest degree of cortical opacification. RESULTS: The prevalence and severity of cortical opacification increased with age with a high degree of concordance (84%) between eyes. For the 47 eyes with cortical opacification > or = 1/8 at baseline, the principal locations of opacification were: inferonasal 63.8%, inferotemporal 17.0%, superonasal 6.4%, and superotemporal 12.8% (P < 0.001, compared with equal distribution by quadrant). Five-year development of new cortical opacification and five-year progression of existing cortical opacification showed even greater preferential occurrence in the inferonasal quadrant of the lens. CONCLUSIONS: In this population, the inferonasal quadrant of the lens is the principal site of cortical opacification in both cross-sectional and longitudinal assessment. This finding is consistent with the hypothesis that sunlight exposure is a significant risk factor for cortical opacification.

Adult↗

PubMed1993

Alcohol use and risk of posterior subcapsular opacities.

We conducted a follow-up study of surgical cases of posterior subcapsular cataracts and their controls to evaluate the possible association of alcohol intake and posterior subcapsular opacities. Two hundred thirty-eight cases and controls were interviewed. Current alcohol intake and usual and maximum weekly consumption ever were assessed. In this population, 57% of the cases and 56% of the controls were nondrinkers, 22% of the cases and 36% of the controls had an average of seven or fewer drinks per week, and 17% of the cases and 8% of the controls had more than seven drinks per week. A matched pair analysis controlling for other known risk factors showed an increased risk associated with heavy alcohol use. Heavy drinkers were more likely to be cases than were nondrinkers (odds ratio, 4.6; P < .05), and light drinkers were not at an increased risk. This result suggests that heavy alcohol consumption may increase the risk of posterior subcapsular cataract.

Alcohol Drinking↗

PubMed1993

Risk factors for trichiasis in women in Kongwa, Tanzania: a case-control study.

Women are at a greater risk compared to men for blinding complications from trachoma. In order to evaluate risk factors in women, 205 cases of trichiasis (TT) were selected from 11 villages in rural Tanzania. Each case of trichiasis was matched to two women of the same age and from the same village, who had no clinical signs of trachoma. Factors associated with trichiasis in a conditional logistic regression included history of trichiasis in the women's mother (odds ratio [OR] = 3.6; 95% confidence interval [CI]: 2.0-6.5); sleeping in a room with a cooking fire during childbearing years (OR = 1.8; 95% CI: 1.2-2.8); a home of wood and earth during childbearing years (OR = 2.1; 95% CI: 1.3-3.3); no adult education classes (OR = 2.2; 95% CI: 1.4-3.4); and five or more deaths among her children (OR = 2.6; 95% CI: 1.3-5.1). Detailed measures of prolonged exposure to child care as a young girl and as a mother showed no significant difference between cases and controls. Results from this study characterize women at high risk for severe disease and eventual blindness in a trachoma endemic area.

Adolescent↗

PubMed1993

Nonocular Chlamydia infection and risk of ocular reinfection after mass treatment in a trachoma hyperendemic area.

PURPOSE: The presence of nasal discharge on a child's face increases the risk of active trachoma, suggesting that Chlamydia trachomatis in nasal secretions may be a possible source of ocular reinfection. The prevalence of chlamydia in nasal secretions and the risk of reinfection after mass treatment was investigated in a hyperendemic area of Tanzania. METHODS: In one village a total of 232 children aged 1 to 7 years were followed before and after mass treatment. Clinical trachoma, and microbiologic evidence of chlamydia, were assessed at baseline, 2 and 4 weeks into mass treatment, and 4 weeks after treatment stopped. The presence of chlamydia in ocular and nasal secretions was determined by polymerase chain reaction-enzyme immunoassay techniques. RESULTS: Of the 232 children, 59% had clinical trachoma and 27% had nasal specimens positive for chlamydia. Children with positive ocular chlamydia specimens and/or clinical trachoma were significantly more likely to have positive nasal specimens. At the end of mass treatment, only 4% of children had positive ocular specimens. However, 1 month after treatment stopped, the incidence of new infection was 21%. The rate of new ocular infections in those who had negative ocular specimens after treatment was similar between those who had positive and those who had negative nasal specimens at baseline. Positive ocular specimens at baseline was not a predictor of risk of new infection after treatment (odds ratio = 1.18, 95% confidence interval = 0.58, 2.40), suggesting these new infections were not the result of latent or persistent organism. CONCLUSIONS: These data do not support a role for nasal secretions in causing reinfection after treatment. One mass topical treatment alone is unlikely to be effective in trachoma hyperendemic areas as shown by the rapid re-emergence of infection.

Base Sequence↗

PubMed1992

The long-term effects of visible light on the eye.

The relationship between exposure to sunlight and senile cataract, age-related macular degeneration, pterygium, and climatic droplet keratopathy was examined in 838 watermen who work on the Chesapeake Bay. The presence and severity of lenticular, corneal, and macular changes were assessed by either clinical examination or from stereo macular photographs. From detailed exposure histories, ocular exposure was estimated for three bands of visible radiation-violet (400 to 450 nm), blue (400 to 500 nm), or all visible (400 to 700 nm)-as well as for UV-A (320 to 340 nm) and UV-B (290 to 320 nm). The results with each band of visible radiation were similar. Neither cortical nor nuclear cataract was associated with ocular exposure to blue or all visible radiation, but pterygium and climatic droplet keratopathy were more common with higher exposures. Compared with age-matched controls, patients with advanced age-related macular degeneration (geographic atrophy or disciform scarring) had significantly higher exposure to blue or visible light over the preceding 20 years (odds ratio, 1.36 [1.00 to 1.85]) but were not different in respect to exposure to UV-A or UV-B. These data suggest that high levels of exposure to blue or visible light may cause ocular damage, especially later in life, and may be related to the development of age-related macular degeneration.

Adult↗

PubMed1992

A controlled trial of surgery for trachomatous trichiasis of the upper lid.

The effectiveness of commonly used procedures to correct trachomatous trichiasis of the upper lid was examined in a clinical trial in Oman. Lids were graded as having minor trichiasis (five or fewer lashes), major trichiasis (more than five lashes), and defective lid closure. Randomly allocated surgery specific for lid grade was completed in 384 lids, of which 369 (96%) were followed up once or twice approximately 9 and 21 months after surgery. The definition of operative success included no evidence of trichiasis and complete lid closure. Tarsal rotation was the most effective operation and was successful in 80% of cases of minor trichiasis, compared with success rates of 29% for electrolysis and 18% for cryoablation. Tarsal rotation was successful in 77% of cases of major trichiasis, compared with a 41% success rate for tarsal advance and rotation. Surgery for major trichiasis produced a significant improvement in visual acuity in operated vs nonoperated fellow eyes in a regression model incorporating the between-eyes correlation of visual acuity.

Cornea↗

PubMed1992

An abbreviated assessment of ocular exposure to ultraviolet radiation.

Individual behaviour has a very large effect on determining the exposure of the eye to solar radiation. To be able to examine the relationship between ocular exposure to ambient ultraviolet radiation and ocular disease, a model was developed previously that assessed cumulative ocular exposure from individual information on work and leisure activities. In this paper, we present a simplified version of the model that uses data on exposure during the middle of the day (9 a.m. to 3 p.m. solar time) during the northern 'summer' months (April to September). The ocular exposure determined by the simplified model is highly correlated with the full model (r = 0.98) and the simplified model predicts 62% of the total ocular exposure. This model should be useful for future epidemiologic studies of sun exposure and eye disease.

Adolescent↗

PubMed1992

The selection of communities for treatment of onchocerciasis with ivermectin.

In areas endemic for onchocerciasis, active community-based treatment with ivermectin is preferred to individual diagnosis and treatment. Ideally, all infected persons should be treated, although initially priorities may have to be set at local or national levels. We suggest that all communities with a prevalence of O. volvulus infection of 20% or more in adult males aged 20 years or over should be treated; and that elsewhere facilities for passive treatment should be provided. In some areas, for logistical reasons, treatment may first have to be started in communities with the highest prevalences (perhaps above 40% or even 60%) and then expanded to all endemic communities. The available data suggest that a rapid assessment method based on the examination for nodules will give a simple, acceptable, non-invasive and reasonably reliable method of identifying the communities that should be treated. If a nodule is detected in at least three men from a sample of 30 men aged 20 years or over, the community can be assumed to have a true prevalence of infection of 20% or more and should be included in community-based treatment.

Adult↗

PubMed1991

Prevalence of lens opacities in surgical and general populations.

The distribution and prevalence of lens opacities were examined and compared among three general population-based groups and a group that underwent cataract surgery. The population-based groups comprised subjects from the Framingham Eye Survey, the National Health and Nutrition Examination Survey, and the study of watermen in Maryland. Comparison among these groups revealed similar frequencies of lens opacities among age groups, with slightly higher rates for older individuals in the watermen study population. Comparison between the watermen and the surgical groups revealed that, of lenses with opacities, posterior subcapsular cataracts were present in a far greater percentage of surgery cases (60.6%) than in general population cases (5.3%). These findings confirm the generally held clinical belief that posterior subcapsular opacities are disproportionally represented in the surgical population and suggest that they cause more significant visual disability than do other types of cataracts.

Adult↗